The present invention claims the benefit of Japanese Patent Application No. 2000-268514, filed Sep. 5, 2000, the entirety of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a swing arm type suspension, and more particularly to a swing arm type suspension for vehicles suitable for enhancing the physical capability of the vehicle, increasing productivity, decreasing vehicle size, and expanding design options of a vehicle body frame.
2. Description of the Background Art
FIG. 9 is a side view of a vehicle 100 provided with a swing arm type suspension 103 of the background art. A power unit 102 including an engine and a change gear is mounted at a lower portion of a vehicle body frame 101 of the vehicle 100. The swing arm type suspension 103 is disposed at the rear of the vehicle body frame 101 and the power unit 102.
The swing arm type suspension 103 is constructed in such a manner that a swing arm 104 is mounted at the rear of the power unit 102 so as to be capable of a swinging motion. This vehicle 100 also includes a rear wheel 105 mounted at a rear end of the swing arm 104, one end of a cushion unit 106 mounted at the rear portion of the vehicle body frame 101, and a first linking member 107 mounted to the swing arm 104 is linked to the other end of the cushion unit 106. A second linking member 108 is mounted to the power unit 102 and is linked to the first linking member 107.
A head pipe 111 is fixed at the front end of the vehicle body frame 101. A front fork 112 is rotatably mounted to the head pipe 111 and is operatively connected with a front wheel 113.
FIG. 10 is a plan view of a vehicle body frame of the background art. A vehicle body frame 101 includes a pair of left and right main frames 115, 115 extending backward from the head pipe 111. A cross beam 116 lying between the respective rear ends of the main frames 115, 115 is provided for lateral support. A mounting portion 117 is provided on the cross beam 116 for mounting the upper end of the cushion unit 106.
In the related art described above, the cross beam 116 is located in a space near the center of the vehicle body. Unfortunately, this region of the vehicle body frame 101 is very suitable for positioning fixtures such as a battery and various electrical components within the vehicle body frame 101. Therefore, by mounting the cross beam 116 in this region, the fixtures described above are required to be relocated to other parts of the vehicle body frame 101.
Accordingly, the weight of these components is moved from the center of the vehicle 100. When these fixtures are relocated, the assembler has to move as he/she assembles those fixtures to the vehicle 100. This results in lowering of productivity and manufacturing efficiency. In addition, it may result in upsizing of the vehicle 100 or it may simply limit the available configurations of the vehicle body frame 101.
When the above-described vehicle 100 of the background art is assembled in the production line, a subassembly that is assembled in advance is often used to attempt to speed the manufacturing process. In the subassembly, the cushion unit 106, the first and the second linking members 107, 108, and the rear wheel 105 mounted to the swing arm 104 are all mounted to the vehicle body, e.g. to a part of the vehicle body frame 101 and the power unit 102.
In this case, the respective ends of the swing arm 104, cushion unit 106, and the second linking member 108 of the subassembly are mounted to the vehicle body frame 101 and the power unit 102. However, since the ends of the cushion unit 106 and the second linking member 108 do not maintain their positioning with respect to the swing arm 104, the subassembly cannot be easily transported. In addition, assemblers cannot easily handle the subassembly when it is assembled to the power unit 102. Therefore, additional time is required in assembling the same.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
It is an object of the present invention to provide a swing arm type suspension for vehicles in which the fixtures and components are concentrated in a central portion of the vehicle body frame in order to enhance the physical capability of the vehicle, increase assembler productivity, reduce vehicle size, and expand available design configurations of a vehicle body frame.
It is an object of the present invention to permit subassemblies to be utilized in the production process, in which the subassembly assembled in the production line can easily be transported and the subassembly can easily be mounted to the side of the vehicle body.
These and other objects of the present invention are accomplished by a swing arm type suspension for vehicles comprising a swing arm having a first end and a second end, the first end pivotably mounted to a pivot shaft provided on a side of a vehicle body so as to be capable of achieving a swinging motion, and the second end includes a portion for rotatably mounting a wheel thereon; and a cushion unit including an upper end and a lower end, the upper end of the cushion unit is mounted to the swing arm, and the lower end of the cushion unit is connected to the side of the vehicle body at a position below the pivot shaft.
In the background art, the upper end of a cushion unit is mounted to the vehicle body frame such as a seat frame or the like. In contrast, the upper end of the cushion unit is mounted to the swing arm in an embodiment of the present invention. Accordingly, it is not necessary to provide a cross pipe or a mounting member for mounting the upper end of the cushion unit within the vehicle body frame. Therefore, fixtures such as electrical components can be concentrated in the center of the vehicle body frame so that the physical capability of the vehicles specifically designed for offroad driving or for racing can be enhanced, and productivity of the vehicle can be increased.
These and other objects of the present invention are further accomplished by a swing arm type suspension for vehicles comprising a swing arm having a first end and a second end, the first end pivotably mounted to a pivot shaft provided on a side of a vehicle body so as to be capable of achieving a swinging motion, and the second end includes a portion for rotatably mounting a wheel thereon; and a cushion unit including an first end and a second end, the first end of the cushion unit is mounted to the swing arm, and the second end of the cushion unit is connected to a linking mechanism at a position below the pivot shaft, wherein the second end of the cushion unit is mounted to a first linking member linked to the swing arm.
When assembling a vehicle in the production line, by assembling the cushion unit, the first and the second linking member, and the rear wheel to the swing arm as a subassembly in the sub-line, both ends of the cushion unit can be positioned with respect to the swing arm. Therefore, only the ends of the swing arm and the second linking member must be mounted to the vehicle body side for assembly of the subassembly to the vehicle body side in the main production line.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.